When the power goes out, whether due to storms, grid failures, or natural disasters, many homeowners wonder: Can a portable generator power a house? The short answer is yes, a portable generator can power a house—but with important limitations, safety considerations, and proper setup.
This comprehensive guide will walk you through everything you need to know about using a portable generator for home backup, including how much of your house it can power, what size you need, connection methods, safety tips, and real-world scenarios.
Table of Contents
- Introduction: Why Use a Portable Generator for Home Backup?
- How Portable Generators Work
- What Can a Portable Generator Power in a House?
- Sizing: What Size Portable Generator Do You Need?
- How to Connect a Portable Generator to Your House
- Safety Considerations
- Step-by-Step: Powering Your House with a Portable Generator
- Limitations of Portable Generators for Home Backup
- Portable vs. Standby Generators
- Frequently Asked Questions
- Conclusion: Is a Portable Generator Right for Your Home?
Introduction: Why Use a Portable Generator for Home Backup?
Power outages can disrupt daily life, spoil food, cause pipes to freeze, and even create dangerous situations for those with medical needs. A portable generator offers a flexible, cost-effective solution for temporary power during blackouts. Unlike whole-house standby generators, portable units are:
- Affordable: Typically $400–$2,000, much less than standby systems.
- Versatile: Can be used for camping, job sites, and outdoor events.
- Easy to store: Compact and mobile, with wheels and handles.
But can they really power your whole house? Let’s find out.
How Portable Generators Work
A portable generator is a self-contained machine that converts fuel (gasoline, propane, or diesel) into electricity using an internal combustion engine and an alternator. The generator produces AC power (usually 120V and/or 240V) that can be used to run appliances, lights, and other devices.
Key features:
- Power output ranges from 1,000 to 12,000+ watts.
- Multiple outlets for plugging in extension cords or connecting to a transfer switch.
- Some models offer dual fuel capability (gasoline and propane).
What Can a Portable Generator Power in a House?
A portable generator can power essential circuits or appliances in your house, but rarely the entire home at once. The number and type of devices you can run depend on the generator’s wattage and your home’s electrical needs.
Typical Essentials Powered by a Portable Generator:
- Refrigerator and freezer
- Sump pump
- Furnace fan or boiler
- Lights
- TV, radio, and phone chargers
- Microwave or coffee maker
- Well pump (if you have one)
- Select outlets for small appliances
What You Usually Can’t Power (with most portables):
- Central air conditioning (unless you have a large generator)
- Electric water heaters
- Electric ranges or ovens
- Whole-house electric heating
The key is to prioritize your most important loads.
Sizing: What Size Portable Generator Do You Need?
Step 1: List Your Essential Appliances
Decide what you want to power during an outage. For most homes, this includes the fridge, sump pump, furnace fan, a few lights, and outlets.
Step 2: Find the Wattage Requirements
Check the labels on your appliances or consult the user manuals. If you can’t find the exact wattage, use a wattage chart or a watt meter.
Step 3: Calculate Total Starting and Running Watts
- Add up the running watts for all devices you want to run at the same time.
- Add the highest starting wattage (not all devices start at once; use the largest surge).
Example:
- Refrigerator: 600 running / 2200 starting
- Sump pump: 800 running / 2000 starting
- Lights: 300 running
- TV: 200 running
- Furnace fan: 700 running / 1400 starting
Total running watts: 600 + 800 + 300 + 200 + 700 = 2,600
Highest starting watts: 2,200 (fridge)
Total needed: 2,600 + (2,200 – 600) = 4,200 watts
Recommended Generator Sizes:
- Essentials only: 3,500–5,000 watts
- Most of the house: 5,000–7,500 watts
- Whole house (with central AC): 10,000+ watts (rare for portables)
Tip: Add a 10–20% safety margin to your total.
How to Connect a Portable Generator to Your House
A. Transfer Switch
A manual transfer switch is the safest, most code-compliant way to connect a portable generator to your home’s electrical system. It allows you to switch selected circuits from utility power to generator power.
Benefits:
- No risk of backfeeding (sending power into utility lines)
- Lets you power hardwired devices (furnace, well pump, etc.)
- Easy to use during an outage
Installation:
Must be installed by a licensed electrician and may require a permit.
B. Interlock Kit
An interlock kit is a mechanical device installed on your main panel that prevents the main breaker and the generator breaker from being on at the same time.
Benefits:
- Less expensive than a transfer switch
- Lets you power any circuit in your panel (within generator limits)
- Code-compliant if installed correctly
Installation:
Also best installed by a licensed electrician.
C. Extension Cord Method
If you don’t have a transfer switch or interlock kit, you can only power individual appliances—not your whole house wiring.
How it works:
- Place the generator outdoors, at least 20 feet from the house.
- Start the generator and let it stabilize.
- Plug heavy-duty extension cords into the generator’s outlets.
- Run cords through a window or door to the appliances you want to power.
Limitations:
- Can’t power hardwired devices (furnace, well pump, etc.)
- Risk of overloading cords or outlets
- Not as convenient or safe as a transfer switch
Safety Considerations
1. Never Backfeed Through a Dryer or Outlet
Plugging a generator into a wall outlet (a practice called “backfeeding”) is illegal, extremely dangerous, and can cause electrocution or fire. Always use a transfer switch or interlock kit.
2. Operate Generators Outdoors Only
Never run a generator in a garage, basement, or enclosed space. Place it at least 20 feet from doors, windows, and vents to avoid carbon monoxide poisoning.
3. Use Outdoor-Rated Equipment
All cords, plugs, and connections must be rated for outdoor use and the generator’s output.
4. Ground Your Generator
Some generators require grounding with a ground rod. Check your owner’s manual and local codes.
5. Don’t Overload the Generator
Know your generator’s wattage limits and don’t exceed them. Overloading can damage the generator and your appliances.
Step-by-Step: Powering Your House with a Portable Generator
1. Prepare Your Generator and Equipment
- Read the generator’s manual.
- Check oil and fuel levels.
- Place the generator outdoors, away from windows and doors.
- Make sure you have the correct cords and adapters.
2. Plug the Generator Into the Power Inlet Box
- Use a heavy-duty generator cord (30A or 50A, 4-prong for 240V).
- Plug one end into the generator’s outlet, the other into the power inlet box.
3. Start the Generator
- Follow the manufacturer’s instructions for starting.
- Let it run for a few minutes to stabilize.
4. Switch the Transfer Switch or Interlock Kit
- For a transfer switch: Flip the selected circuits from “Line” (utility) to “Gen” (generator).
- For an interlock kit: Turn off the main breaker, slide the interlock, and turn on the generator breaker.
5. Power Your Home
- Only turn on circuits/appliances that your generator can handle.
- Monitor the load to avoid overloading the generator.
6. Refueling and Shutdown
- Never refuel a running or hot generator.
- Turn off all loads, shut down the generator, and let it cool before refueling.
Limitations of Portable Generators for Home Backup
- Limited Power: Most portables can’t run everything at once.
- Manual Operation: You must start, refuel, and manage the generator yourself.
- Noise: Generators can be loud, especially open-frame models.
- Fuel Storage: You need to store gasoline or propane safely.
- No Automatic Start: Unlike standby generators, portables don’t start automatically when the power goes out.
Portable vs. Standby Generators
| Feature | Portable Generator | Standby Generator |
|---|---|---|
| Power Output | 1,000–12,000+ watts | 7,000–48,000+ watts |
| Startup | Manual | Automatic |
| Installation | Plug-and-play/transfer | Permanent, pro install |
| Fuel | Gasoline/Propane/Diesel | Natural Gas/Propane |
| Cost | $400–$2,000 | $5,000–$15,000+ |
| Noise | Louder | Quieter (enclosed) |
| Mobility | Portable | Fixed |
Frequently Asked Questions
1. Can I run my whole house on a portable generator?
Only if you have a large enough generator (10,000+ watts) and a transfer switch. Most people power essentials only.
2. Can I plug my generator into a dryer or range outlet?
No. This is dangerous, illegal, and can cause electrocution or fire.
3. Do I need a transfer switch?
Yes, if you want to power your home’s circuits safely and legally. Extension cords are only for individual appliances.
4. How long can a portable generator run continuously?
Most can run 8–12 hours on a tank of fuel. For longer use, shut down for refueling and maintenance.
5. Is it safe to run a generator in the rain?
No. Use a generator tent or cover designed for outdoor use, but never enclose the generator completely.
Conclusion: Is a Portable Generator Right for Your Home?
Can a portable generator power a house?
Yes, but with limitations. A portable generator can keep your essential appliances and circuits running during a power outage, providing comfort and safety until utility power is restored. The key is to size your generator correctly, use a transfer switch or interlock kit for safe connection, and follow all safety guidelines.
Key Takeaways:
- Most homes can get by with a 3,500–7,500 watt portable generator for essentials.
- Use a transfer switch or interlock kit for safe, code-compliant operation.
- Never backfeed or run a generator indoors.
- Plan ahead, test your setup, and keep fuel and maintenance supplies on hand.
With the right setup and knowledge, your portable generator will be a reliable ally in any emergency—keeping your home safe, comfortable, and powered up when you need it most.